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S Marina

Publications and source records attributed to S Marina.

At least 19 recordsLinked to original sources
PubMed1991

XY-trivalent association and synaptic anomalies in a male carrier of a Robertsonian t(13;14) translocation.

Synaptonemal complexes were analysed in 91 pachytenes from a patient carrier of a Robertsonian translocation 45XY, t(13;14). Electron microscopic studies were carried out in 36 pachytenes. In some cases, sequential light microscopy/electron microscopic images were obtained (16/36). As the resolution of the light microscope does not allow an accurate characterization of anomalies, only EM images have been taken into account. Association of the trivalent and the sex vesicle was detected in 8 of 36 pachytenes (22.2%). Synaptic anomalies (25%), fragmentation of synaptonemal complexes (11.1%) or both (2.8%) were seen in 14 of 36 nuclei. According to previous studies, synaptic anomalies may produce a spermatogenic arrest. However, it has been suggested that synaptic anomalies may be the result of a process of cell degeneration, and not its cause. The non-random relationship between the sex vesicle and the translocation trivalent may result from the tendency of unpaired segments to associate with each other after homology search is relaxed and heterologous synaptic adjustment is allowed.

Adult↗
PubMed1990

Karyotype screening of potential sperm donors for artificial insemination.

Cytogenetic studies were carried out in 100 potential semen donors for artificial insemination (AI) before they underwent the routine procedures for acceptance or rejection into the programme, namely medical history, physical examination and blood and semen analyses. Results were only compared at the end of the study. In 80 cases, the karyotype was normal; 12 males showed polymorphic chromosome variants; seven had pericentric inversions of heterochromatic regions; one had a short inversion of chromosome 2; and in one case centromere fragility was observed. Six of the 12 males with normal variants were accepted into the programme and four of them had fathered from one to 13 normal children at the end of the study; the other six had been rejected, four of them because of abnormal seminograms, and another two because the motility control of the frozen semen was negative. Of the seven males with pericentric inversions, one dropped out of the programme; four were accepted and three of them had produced from two to five normal children at the end of the study; two had been rejected due to abnormal seminograms. The individual with centromere fragility was accepted and had produced four normal children at the end of the series. Our conclusion is that although cytogenetic studies of potential donors for AI would be desirable, routine screening for chromosome anomalies is not justified at present.

Genetic Testing↗
PubMed1990

[Xanthogranuloma juvenile combined with neurofibromatosis].

Xanthogranuloma juvenile is a rare condition of childhood. The disease typically begins in infancy or early childhood and despite the number of papules, eventuates in cure in two to five years. The present report describes an extremely rare combination of xanthogranuloma juvenile with neurofibromatosis.

Biopsy↗
PubMed1986

Meiotic chromosome studies and synaptonemal complex analyses by light and electron microscopy in 47 infertile or sterile males.

Mitotic and meiotic chromosome studies and synaptonemal complex analyses by light and electron microscopy have been carried out in a selected series of 47 infertile or sterile males with highly abnormal seminograms, affecting the number of spermatozoa, their morphology and/or motility. In 46 cases, the karyotype was 46,XY. One patient had a 13/14 translocation. With the exception of the patient with a 13/14 translocation, and three patients with desynapsis (8.5%), all other cases showed either normal or absent metaphase I figures. However, synaptonemal complex analysis by light and electron microscopy demonstrated the presence of pairing anomalies (desynapsis, fragmented or irregular synaptonemal complexes) in 31.9% of the patients studied. The total number of synaptic anomalies observed (40.4%) is higher than in a former light microscopy study of 111 infertile or sterile patients (28.8%) probably because the higher resolution of the electron microscope permits the characterization of some anomalies that cannot be detected with the light microscope. The electron microscope should therefore be used in all cases in which the light microscope provides doubtful results.

Chromosomes, Human↗
PubMed1984

Meiotic studies and synaptonemal complex analysis in two infertile males with a 13/14 balanced translocation.

Meiotic and synaptonemal complex studies by light and electron microscopy have been carried out in two infertile males with a balanced 13/14 translocation. As expected, all metaphase I figures in conventional meiotic preparations contained a chain trivalent. Synaptonemal complex studies showed typical trivalent images with incomplete pairing of the acrocentric elements in the cis configuration. A review of the literature shows that the fertility of these patients is quite variable. All of them show a slightly reduced number of chiasmata (mean 46.6). Pairing in cis, as detected by electron microscopic studies, does not seem to have a prognostic value.

Adult↗
PubMed1984

Development and behavior of synaptonemal complexes in human spermatocytes by light and electron microscopy.

We describe in this paper the human male synaptic cycle using light and electron microscopy and the distribution of cells in the different stages of prophase I. The pattern of chromosome pairing and synapsis is an important tool to determine accurately whether a given synaptic behavior in infertile or sterile men is really abnormal or not. The relationship of prepachytene to pachytene cells is also important for the diagnosis of the different types of meiotic arrest at the primary spermatocyte level.

Cell Nucleus↗
PubMed1983

Meiotic studies in a series of 1100 infertile and sterile males.

Meiotic studies have been carried out in a series of 1100 infertile and sterile males. Of these, 599 cases have been studied in testicular biopsy, and 501, in semen samples. This is the largest meiotic series published so far. The incidence of meiotic anomalies was 4.3%. The most frequent chromosome abnormality was desynapsis (3.7%). However, the number of cases with a meiotic arrest, usually due (73.9%) to synaptic anomalies in prophase I, was much higher (18.4%). An attempt is made to correlate the incidence of meiotic anomalies with the results of semen analysis. We discuss the prognosis of desynapsis, based on 41 cases studied, and reevaluate the results obtained in semen samples as compared with our previous results.

Chromosome Aberrations↗
PubMed1982

Meiotic and synaptonemal complex studies in 45 subfertile males.

We describe the results of meiotic and synaptonemal complex (SC) studies in a selected series of 45 subfertile males with different meiotic and seminal alterations. SC anomalies (pairing anomalies, fragmented SCs, or presynaptic arrest) were observed in 32 cases (71.1%). In 31% of the abnormal cases, meiotic anomalies could only be detected through the study of SCs. The origin of synaptic anomalies may be related to the assembly of myosin molecules along the chromosomes. SC analysis should become routine in the study of subfertile males.

Biopsy↗
PubMed1982

Meiotic and synaptonemal complex studies in a 14/21 translocation carrier.

Meiotic studies in a sterile carrier of a 14/21 translocation showed a meiotic arrest, with degeneration of primary spermatocytes. Silver staining of pachytene cells revealed the presence of a trivalent. Its synaptonemal complex was quite similar to that described in previous light and electron microscopy studied in mammalian species. The observation of a trivalent with pairing in trans-configuration and the presence of desynaptic synaptonemal complexes in early pachytene could explain the relatively high incidence of non-disjunction in human D/G translocations and the spermatogenic disintegration sometimes seen in these cases.

Adult↗
PubMed1981

Meiotic behaviour of two human reciprocal translocations.

The meiotic behaviour of two male human reciprocal translocations is described. One patient had an unbalanced son and a chain configuration. The second had a stillborn child and a ring corresponding to an adjacent I segregation. The meiotic behaviour of chromosomal rearrangements must be investigated for proper genetic counselling.

Adult↗
PubMed1981

[Polyorchidism (author's transl)].

The authors describe two new cases of polyorchidism. In the first case, they removed a testis which had a better seminal line than the testis preserved. In the other case, a conservative attitude was adopted. A review of the literature is followed by a discussion of the benefits of conservative therapy.

Adolescent↗